44 –Gastrointestinal Disease: Etiologic Agents Speaker ...
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©2021 Infectious Disease Board Review, LLC 44 – Gastrointestinal Disease: Etiologic Agents Speaker: Herbert DuPont, MD Gastrointestinal Disease: Causative Agents Herbert L. DuPont, MD Professor, Infectious Diseases, Epidemiology The University of Texas McGovern Medical School School of Public Health Clinical Professor, Infectious Diseases Baylor College of Medicine and MD Anderson Cancer Disclosures of Financial Relationships with Relevant Commercial Interests • None OBJECTIVES • • • • THE IMPORTANCE OF DIARRHEA IN THE UNITED STATES • • • DEATH FROM DIARRHEA IN U.S. • 11,255 deaths/year: 83% of deaths occur in adults ≥ 65 years of age; Pediatric deaths 369/year • C. difficile infection (CDI) the most common cause of death 7,903* year (70% of total) • Noroviruses (797/year) often in elderly in hospitals or nursing homes • Salmonella (378) and • Listeria (260) Hall, AJ et al. Clin Infect Dis 2011;55:216-23 CDC http://www.cdc.gov/foodborneburden/2011- foodborne-estimates.html *CDC data 29,000 deaths annually PATHOGEN COMMUNICABILITY ALL INFECTIOUS DISEASES SHOW A DOSE THRESHOLD FOR ILLNESS Pathogen Group Expected Inoculum Size Highest rate of transmissibility*: Shigella, Noroviruses 10 to 100 organisms High rate of transmissibility: Giardia, Cryptosporidium, Salmonella (infants only) 80-500 organisms Low communicability: Shiga toxin- producing E. coli, Salmonella (older children/adults), Campylobacter 500 to 100,000 organisms Absence of communicability: enteroinvasive and enterotoxigenic E. coli (EIEC, ETEC) and Vibrio cholerae 100,000 to > 1,000,000 organisms *low inoculum requirement, stability in environment, reservoir in children Immunocompromised/elderly people, infants, those on proton pump inhibitors may be susceptible to lower inoculum sizes
Transcript of 44 –Gastrointestinal Disease: Etiologic Agents Speaker ...
©2021 Infectious Disease Board Review, LLC
44– GastrointestinalDisease:EtiologicAgentsSpeaker:HerbertDuPont,MD
Gastrointestinal Disease: Causative Agents
Herbert L. DuPont, MDProfessor, Infectious Diseases, Epidemiology
The University of Texas McGovern Medical SchoolSchool of Public Health
Clinical Professor, Infectious DiseasesBaylor College of Medicine and MD Anderson Cancer
Disclosures of Financial Relationships with Relevant Commercial Interests
• None
OBJECTIVES•
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THE IMPORTANCE OF DIARRHEA IN THE UNITED STATES
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DEATH FROM DIARRHEA IN U.S.
• 11,255 deaths/year: 83% of deaths occur in adults ≥ 65 years of age; Pediatric deaths 369/year
• C. difficile infection (CDI) the most common cause of death 7,903* year (70% of total)
• Noroviruses (797/year) often in elderly in hospitals or nursing homes
• Salmonella (378) and• Listeria (260)
Hall, AJ et al. Clin Infect Dis 2011;55:216-23CDC http://www.cdc.gov/foodborneburden/2011-
foodborne-estimates.html*CDC data 29,000 deaths annually
PATHOGEN COMMUNICABILITYALL INFECTIOUS DISEASES SHOW A DOSE THRESHOLD FOR ILLNESS
Pathogen Group Expected Inoculum SizeHighest rate of transmissibility*: Shigella, Noroviruses
10 to 100 organisms
High rate of transmissibility: Giardia, Cryptosporidium, Salmonella (infants only)
80-500 organisms
Low communicability: Shiga toxin-producing E. coli, Salmonella (older children/adults), Campylobacter
500 to 100,000 organisms
Absence of communicability: enteroinvasive and enterotoxigenic E. coli (EIEC, ETEC) and Vibrio cholerae
100,000 to > 1,000,000 organisms
*low inoculum requirement, stability in environment, reservoir in childrenImmunocompromised/elderly people, infants, those on proton pump inhibitors may be susceptible to lower inoculum sizes
©2021 Infectious Disease Board Review, LLC
44– GastrointestinalDisease:EtiologicAgentsSpeaker:HerbertDuPont,MD
QUESTION #1
A.B.C.D.E.
VIRAL GASTROENTERITISROTAVIRUS
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NOROVIRUSES
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SHIGA TOXIN-PRODUCING E. COLI INFECTION (~300,000 CASES IN U.S.)
E. COLI O157SORBITOL-NON-FERMENTING
SORBITOL-MACCONKEY AGAR & O157 SEROTYPING
E. coli non-O157Sorbitol-positive, test stools, broth or culture plate for Stx 1 and 2 by EIA and if positive send E. coli to Health Lab
Hemorrhagiccolitis
DysenteryHemolytic Uremic
Syndrome
85%
13%9%
9%
STEC strains are threatening our food supply
SHIGA TOXIN PRODUCTION UNDER PHAGE CONTROL
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WHAT OF THE FOLLOWING IS TRUE ABOUT ECULIZUMAB TREATMENT OF HUS?
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B. TREATED PATIENTS ARE SUSCEPTIBLE TOMENINGOCOCCAL INFECTIONS
C.D.
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QUESTION # 2 NON-TYPHOID SALMONELLOSIS
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44– GastrointestinalDisease:EtiologicAgentsSpeaker:HerbertDuPont,MD
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•Marzel, A et al. Clin Infect Dis 2016;62:879-86
NON-TYPHOID SALMONELLOSIS PROTOZOAL PATHOGENS CAUSE PROTRACTED DIARRHEA
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Giardia E. histolytica
Cryptosporidium CyclosporaSerology helpful in hepatic abscess as stoolsoften negative
SEAFOOD FOODBORNE DISEASESNEUROTOXIGENIC ILLNESSES:
•PARALYTIC SHELLFISH
•CIGUATERA:
•NEUROTOXIN INHALATION OR SHELLFISH POISONING
•PUFFERFISH
CHEMICAL ILLNESS:•SCROMBROID
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SEAFOOD FOODBORNE DISEASES
WHAT’S NEW TRAVELERS’ DIARRHEAESBL or MDR EnterobacteriaceaeRisk Factors:• Travel to tropical and semitropical areas, especially Asia (highest for travel to India)• Diarrhea increases rate and receipt of antibiotics further increases riskEndogenous Infections* or Spread to Family Duration of Colonization After Returning Home• < 3 months to 12 months• Shorter than when acquired in a hospital•Treat only more severe Travelers’ diarrhea
Extended spectrum beta lactamase-producingEnterobacteriaceae
Jiang Z-D, DuPont HL
CRO30
CTX30
AMC30
CRO30 = Ceftriaxone 30µgCTX30 = Cefotaxime 30µgAMC30 = Amoxicillin-Clavulanic Acid 30µg
DIAGNOSTIC APPROACHES IN INFECTIOUS DISEASES MOVING TO PCR
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The Positives
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44– GastrointestinalDisease:EtiologicAgentsSpeaker:HerbertDuPont,MD
CHALLENGES MULTIPLEX PCR DIAGNOSIS
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• Requires clinical judgement & correlation
BiofireVerigene Luminex
Biocode
The Negatives
CHALLENGES MULTIPLEX PCR DIAGNOSIS
*Clark SD et al. Open Forum Infect Dis 2019;6(4).doi:10.1093/ofid/ofz162
BiofireVerigene Luminex
Biocode
2017 INFECTIOUS DIARRHEA GUIDELINES (HIGHLIGHTS)
• EXERCISE CLINICAL JUDGMENT WHEN INTERPRETING PCR-BASED RESULTS
• PERFORM REFLEX CULTURES WHEN AN ORGANISM IS IDENTIFIED BY PCR FOR EPIDEMIOLOGYAND SUSCEPTIBILITY TESTING
• FECAL LEUKOCYTE, LACTOFERRIN, CALPROTECTIN ARE NOT ROUTINELY INDICATED
• DIAGNOSTIC TESTING IS NOT INDICATED FOR TRAVELERS’ DIARRHEA UNLESS DIARRHEA PERSISTS>14 DAYS, CONSIDER C. DIFFICILE IF ANTIBIOTIC EXPOSURE. TD CAN TRIGGERINFLAMMATORY BOWEL DISEASE OR IRRITABLE BOWEL SYNDROME
• MONITOR CR/HB IN PATIENTS WITH STEC IDENTIFIED IN STOOLS AT RISK FOR HUS, EXAMINEPERIPHERAL SMEAR FOR SCHISTOCYTES
• PERFORM ENDOSCOPY FOR PERSISTENT, UNEXPLAINED DIARRHEA. EVALUATE HIV ANDLYMPHOPENIC PATIENTS FOR CMV AND MAC
Shane, et. al. CID 2017:65 e45-80
ORGANISM-SPECIFIC THERAPY• Shigellosis – Fluoroquinolone or
azithromycin• Non-typhoid salmonellosis – only
with sepsis - fluoroquinolone or 3rd
generation cephalosporin• Campylobacteriosis – Azithromycin
or erythromycin• STEC diarrhea – none• Non-cholera Vibrio diarrhea – as
shigellosis• Cholera – doxycyline
• Viral gastroenteritis – ORT, ? Bismuth subsalicylate
• Giardiasis – Tinidazole or nitazoxanide
• Cryptosporidiosis - nitazoxanide• Cyclosporiasis or Cystoisosporiasis –
TMP/SMX• Enterocytozoon diarrhea –
Albendazole• Intestinal amoebiasis –
metronidazole plus diloxanide furoate or paromomycin
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Where Will You Be WhenDiarrhea Strikes?
